The Best Time for Repotting Orchids and Changing the Growing Medium, Plus Experience Shared

Orchids are perennial herbaceous plants, and their growth rate is relatively slow. Like other plants, orchids also need a relatively stable environment to grow, which means the growing medium in the pot and the surrounding environment need to be relatively stable, and frequent repotting and medium changes are not suitable.

Under the condition of providing orchids with a relatively stable environment, orchids can grow very well for many consecutive years, and will get better year after year. This I know from personal experience. Orchid enthusiasts who pay attention to observation in daily life should also notice that in the first year after repotting, the plants do not grow very well, but starting from the second year the growth is clearly better than before, and the new shoots are also stronger than in the first year. This means that after a relatively long period, the orchids have begun to adapt to the environment you have provided for them. And when they have just begun to adapt to this environment, you want to change it again. Tossing them back and forth like this will only make your plants weaker and weaker the more you grow them. The purpose of repotting is to divide the plants or change to fresh growing medium so that the orchids grow better, but repotting too frequently does just the opposite.

Especially now that most of us use granular growing medium, after repotting, the degree of contact between the orchid roots and the medium will be greatly reduced, thereby greatly affecting root growth and the absorption of nutrients. Therefore, unless there is something wrong with my potted orchids, I generally very rarely repot and change the medium within 2 years.

As for the growing medium, I think growing orchids is actually also a process of cultivating the medium. Orchid enthusiasts who have kept fish all know that to keep fish, you first cultivate the water, and the same principle applies here. Once the medium is well cultivated, the plants will grow better and better. Under proper management, as long as the newly grown shoots do not show obvious signs of being weaker than the previous generation, it means the medium is basically workable and can continue to be used. Many orchid enthusiasts, however, dump out and replace or throw away the medium just when a pot of medium has not yet been fully cultivated and matured, or has just been cultivated and matured. What a pity. Those who cannot bear to throw away the used medium will sometimes also use old medium to grow some common orchids. You may find that these common orchids grown in old medium grow far better than those you grow in new medium. As long as we think it over carefully, it is not hard to figure out the reason.

As for the growing medium, as long as it has not been used to grow diseased orchids, I screen all of it and reuse it. Especially mixed granular medium, as long as its properties have not changed, there should be no problem reusing it for ten or eight years. The old medium that has been replaced, as long as the orchids previously grown in it showed no adverse reactions, should be added to the new medium as much as possible to preserve the orchid mycorrhizal community already formed in the original medium. Also, do not let the properties and proportions of the new and old medium change too much. Alternatively, through growing you can sum up whether the old medium has any shortcomings, and by adding some other medium to adjust the ratio, it may be much better than using a completely new medium mix.